Section 3 (2-3) Earthquake Hazards and Safety

---

Vocabulary

---

Liquefaction- a damage caused by a earthquake which the moist soil turns to mud
After shock- a earthquake that happens after the main earthquake in the same place
Tsunamis- a large wave caused by an earthquake
base-isolated building- a structure designed to cut down on the amount of energy that hits it during an earthquake

---

Outline

---

How Earthquakes Cause Damage

• Big earthquakes can cause a great damage.
• The S waves damage first when you are near a epicenter.
• Local Soil Conditions
  • When the seismic waves moves from hard rock to loose soil, it shakes more violently than on the rock.
• Liquefaction
  • When the moist soil shakes, the soil turns in to liquid mud.
  • It can trigger land slides.
• After shocks
  • The after shock occurs after a main earthquake strikes.
  • It may strike hours, days, or even months later.
• Tsunamis
  • Tsunamis is a big waves caused by an earthquake.
  • The waves spread from the epicenter.
  • The waves gets bigger when the waves approach to land.

Making Building Safer

• Earthquake deaths are mostly from the falling objects.
• The strong and flexible buildings withstand the earthquake.
• The Choice of Location
  • The steep hill may cause the land slides.
  • The filled land can shake violently.
  • The land near the faults shake violently than the other places.
  • The further from the fault, the less shaking there will be.
• Construction Methods
  • Old building usually can not with stand the earthquake.
  • New buildings are designed to withstand the shock of earthquake.
  • Old buildings can be designed to make them earthquake resistant.

Protecting Yourself During an Earthquake

• For your own safety when you are indoor, you should drop and shield yourself beneath a table or a desk. Also when there are no desk or table available crouch beneath a inner wall.

Diagram of base isolated-building and fixed-base building